Featured Research

from universities, journals, and other organizations

Sound Waves Save Roads

Date:
September 24, 2009
Source:
Vetenskapsrådet (The Swedish Research Council)
Summary:
Every year European roads are built and repaired to the tune of several billion Euros. Intensive efforts are underway all over the world to get 'more road for your money' by developing better methods for both design and quality control of materials. One problem is that today there are no good methods for checking how robustly and safely the roads were built. Therefore they often don't last as long as they were supposed to and more money has to go to road construction. But now a young scientist has developed a method where sound waves can reveal what a road looks like underneath and thereby show whether it is being properly built.

Every year European roads are built and repaired to the tune of several billion Euros. Intensive efforts are underway all over the world to get 'more road for your money' by developing better methods for both design and quality control of materials. One problem is that today there are no good methods for checking how robustly and safely the roads were built. Therefore they often don't last as long as they were supposed to and more money has to go to road construction.

But now a young scientist has developed a method where sound waves can reveal what a road looks like underneath and thereby show whether it is being properly built. According to the Swedish Road Administration, the method, which is expected to become the new standard, may entail major quality enhancements and cost savings.

Damage to bridges, tunnels, dams, and nuclear power plants can be uncovered using this technology, and dangerous accidents can thereby be prevented. Today most prognoses are based on educated guesses from previous experience, which often prove to be wrong. Since a road consists of many different materials - gravel, bitumen, air, water - it's difficult to predict how it will respond to future traffic and environmental loads. Because roads, unlike buildings, for instance, are 'built into' the ground, it's hard to inspect them visually.

"But with sound waves, roughly as with x-rays and ultrasound, you can obtain information about the composition and stiffness of the material on a computer screen. This allows you to monitor whether work is being done properly, thus ensuring that the road will last as long and withstand loads as well as projected. Today inspectors typically have to drill cores and break up asphalt and concrete samples, instead of using this non-destructive type of testing," explains Nils Rydén, a researcher in engineering geology at the Faculty of Engineering, Lund University, who developed the technology.

Some roads only hold up for a couple of years, according to Nils Rydén, either because the materials were not sufficiently compacted, because the road bed was too soft, or because it was raining when the road was built, weaknesses that were then not discovered when the final inspection took place.

Major portions of the country's infrastructure were constructed 40 to 50 years ago and will soon need to be repaired, on the one hand, because they are worn out and, on the other, because they were dimensioned for 40 years, which was the standard back then. That time has now gone by and the question arise if and for how long the structure can be used. The concrete foundations of the Swedish nuclear power stations are in the same situation. Here, too, there have been no methods for inspecting and verifying whether they are in good condition.

"A road can't collapse into the earth and constitute the same safety risk as a bridge or a hydropower facility, which can in fact collapse, as has recently happened in the US and Russia," says Nils Rydén, who for the last couple of years has been busy, alongside his research, helping the Road Administration and various construction companies by tuning his technology so they can use it for their particular needs.

Nils Rydén was inspired to test the possibility of inspecting roads with sound when he wrote his master's thesis in 2000. At that time there were similar projects underway abroad, in the US, for instance, but today the Swedish method is the most advanced technology, according to Nils Rydén. Sound waves have previously been used to inspect material in the auto and aircraft industry and to find oil and gas deposits underground.

The technology in brief

Non-destructive testing with sound waves is based on measuring the dispersion of sound waves in constructions in order to 'see,' roughly in the same way as in medical ultrasound examinations, the stiffness and thickness of the materials involved as well as any cracks, etc. The velocity of the sound waves is directly related to the stiffness of the material, and differences in stiffness produce reflections that can be utilized for measuring the thickness of layers and for detecting hidden damage. When sound waves are used for measuring, rather low frequencies are employed, 50-10,000 Hz. Frequencies above 20,000 Hz are usually called ultrasound. The reason available ultrasound technology cannot be used is that ultrasound waves disappear after only a few decimeters in asphalt and concrete. X-rays can also be used for concrete, etc., but this is extremely expensive and complicated compared with sound waves.


Story Source:

The above story is based on materials provided by Vetenskapsrådet (The Swedish Research Council). Note: Materials may be edited for content and length.


Cite This Page:

Vetenskapsrådet (The Swedish Research Council). "Sound Waves Save Roads." ScienceDaily. ScienceDaily, 24 September 2009. <www.sciencedaily.com/releases/2009/09/090923105817.htm>.
Vetenskapsrådet (The Swedish Research Council). (2009, September 24). Sound Waves Save Roads. ScienceDaily. Retrieved July 30, 2014 from www.sciencedaily.com/releases/2009/09/090923105817.htm
Vetenskapsrådet (The Swedish Research Council). "Sound Waves Save Roads." ScienceDaily. www.sciencedaily.com/releases/2009/09/090923105817.htm (accessed July 30, 2014).

Share This




More Science & Society News

Wednesday, July 30, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Britain Testing Driverless Cars on Roadways

Britain Testing Driverless Cars on Roadways

AP (July 30, 2014) — British officials said on Wednesday that driverless cars will be tested on roads in as many as three cities in a trial program set to begin in January. Officials said the tests will last up to three years. (July 30) Video provided by AP
Powered by NewsLook.com
Health Insurers' Profits Slide

Health Insurers' Profits Slide

Reuters - Business Video Online (July 30, 2014) — Obamacare-related costs were said to be behind the profit plunge at Wellpoint and Humana, but Wellpoint sees the new exchanges boosting its earnings for the full year. Fred Katayama reports. Video provided by Reuters
Powered by NewsLook.com
China's Drone King Says the Revolution Depends on Regulators

China's Drone King Says the Revolution Depends on Regulators

Reuters - Business Video Online (July 30, 2014) — Comparing his current crop of drones to early personal computers, DJI founder Frank Wang says the industry is poised for a growth surge - assuming regulators in more markets clear it for takeoff. Jon Gordon reports. Video provided by Reuters
Powered by NewsLook.com
London Mayor Outlines 50-Year Vision Ahead of Population Rise

London Mayor Outlines 50-Year Vision Ahead of Population Rise

AFP (July 30, 2014) — London Mayor Boris Johnson outlined his infrastructure plan for the British capital over the next 50 years on Wednesday, with a focus on how to cope with a population expected to reach 11 million. Duration: 00:57 Video provided by AFP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:  

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile iPhone Android Web
Follow Facebook Twitter Google+
Subscribe RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins